async_tx: add support for asynchronous RAID6 recovery operations
async_raid6_2data_recov() recovers two data disk failures async_raid6_datap_recov() recovers a data disk and the P disk These routines are a port of the synchronous versions found in drivers/md/raid6recov.c. The primary difference is breaking out the xor operations into separate calls to async_xor. Two helper routines are introduced to perform scalar multiplication where needed. async_sum_product() multiplies two sources by scalar coefficients and then sums (xor) the result. async_mult() simply multiplies a single source by a scalar. This implemention also includes, in contrast to the original synchronous-only code, special case handling for the 4-disk and 5-disk array cases. In these situations the default N-disk algorithm will present 0-source or 1-source operations to dma devices. To cover for dma devices where the minimum source count is 2 we implement 4-disk and 5-disk handling in the recovery code. [ Impact: asynchronous raid6 recovery routines for 2data and datap cases ] Cc: Yuri Tikhonov <yur@emcraft.com> Cc: Ilya Yanok <yanok@emcraft.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: David Woodhouse <David.Woodhouse@intel.com> Reviewed-by: Andre Noll <maan@systemlinux.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams
Родитель
b2f46fd8ef
Коммит
0a82a6239b
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@ -67,6 +67,10 @@ xor_val - xor a series of source buffers and set a flag if the
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pq - generate the p+q (raid6 syndrome) from a series of source buffers
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pq_val - validate that a p and or q buffer are in sync with a given series of
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sources
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datap - (raid6_datap_recov) recover a raid6 data block and the p block
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from the given sources
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2data - (raid6_2data_recov) recover 2 raid6 data blocks from the given
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sources
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3.3 Descriptor management:
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The return value is non-NULL and points to a 'descriptor' when the operation
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@ -18,3 +18,8 @@ config ASYNC_PQ
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tristate
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select ASYNC_CORE
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config ASYNC_RAID6_RECOV
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tristate
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select ASYNC_CORE
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select ASYNC_PQ
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@ -3,3 +3,4 @@ obj-$(CONFIG_ASYNC_MEMCPY) += async_memcpy.o
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obj-$(CONFIG_ASYNC_MEMSET) += async_memset.o
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obj-$(CONFIG_ASYNC_XOR) += async_xor.o
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obj-$(CONFIG_ASYNC_PQ) += async_pq.o
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obj-$(CONFIG_ASYNC_RAID6_RECOV) += async_raid6_recov.o
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@ -0,0 +1,448 @@
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/*
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* Asynchronous RAID-6 recovery calculations ASYNC_TX API.
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* Copyright(c) 2009 Intel Corporation
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*
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* based on raid6recov.c:
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* Copyright 2002 H. Peter Anvin
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/dma-mapping.h>
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#include <linux/raid/pq.h>
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#include <linux/async_tx.h>
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static struct dma_async_tx_descriptor *
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async_sum_product(struct page *dest, struct page **srcs, unsigned char *coef,
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size_t len, struct async_submit_ctl *submit)
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{
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struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
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&dest, 1, srcs, 2, len);
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struct dma_device *dma = chan ? chan->device : NULL;
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const u8 *amul, *bmul;
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u8 ax, bx;
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u8 *a, *b, *c;
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if (dma) {
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dma_addr_t dma_dest[2];
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dma_addr_t dma_src[2];
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struct device *dev = dma->dev;
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struct dma_async_tx_descriptor *tx;
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enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
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dma_dest[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
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dma_src[0] = dma_map_page(dev, srcs[0], 0, len, DMA_TO_DEVICE);
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dma_src[1] = dma_map_page(dev, srcs[1], 0, len, DMA_TO_DEVICE);
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tx = dma->device_prep_dma_pq(chan, dma_dest, dma_src, 2, coef,
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len, dma_flags);
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if (tx) {
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async_tx_submit(chan, tx, submit);
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return tx;
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}
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}
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/* run the operation synchronously */
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async_tx_quiesce(&submit->depend_tx);
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amul = raid6_gfmul[coef[0]];
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bmul = raid6_gfmul[coef[1]];
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a = page_address(srcs[0]);
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b = page_address(srcs[1]);
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c = page_address(dest);
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while (len--) {
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ax = amul[*a++];
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bx = bmul[*b++];
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*c++ = ax ^ bx;
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}
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return NULL;
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}
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static struct dma_async_tx_descriptor *
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async_mult(struct page *dest, struct page *src, u8 coef, size_t len,
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struct async_submit_ctl *submit)
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{
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struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
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&dest, 1, &src, 1, len);
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struct dma_device *dma = chan ? chan->device : NULL;
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const u8 *qmul; /* Q multiplier table */
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u8 *d, *s;
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if (dma) {
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dma_addr_t dma_dest[2];
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dma_addr_t dma_src[1];
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struct device *dev = dma->dev;
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struct dma_async_tx_descriptor *tx;
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enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
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dma_dest[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
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dma_src[0] = dma_map_page(dev, src, 0, len, DMA_TO_DEVICE);
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tx = dma->device_prep_dma_pq(chan, dma_dest, dma_src, 1, &coef,
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len, dma_flags);
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if (tx) {
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async_tx_submit(chan, tx, submit);
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return tx;
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}
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}
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/* no channel available, or failed to allocate a descriptor, so
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* perform the operation synchronously
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*/
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async_tx_quiesce(&submit->depend_tx);
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qmul = raid6_gfmul[coef];
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d = page_address(dest);
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s = page_address(src);
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while (len--)
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*d++ = qmul[*s++];
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return NULL;
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}
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static struct dma_async_tx_descriptor *
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__2data_recov_4(size_t bytes, int faila, int failb, struct page **blocks,
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struct async_submit_ctl *submit)
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{
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struct dma_async_tx_descriptor *tx = NULL;
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struct page *p, *q, *a, *b;
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struct page *srcs[2];
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unsigned char coef[2];
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enum async_tx_flags flags = submit->flags;
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dma_async_tx_callback cb_fn = submit->cb_fn;
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void *cb_param = submit->cb_param;
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void *scribble = submit->scribble;
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p = blocks[4-2];
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q = blocks[4-1];
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a = blocks[faila];
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b = blocks[failb];
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/* in the 4 disk case P + Pxy == P and Q + Qxy == Q */
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/* Dx = A*(P+Pxy) + B*(Q+Qxy) */
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srcs[0] = p;
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srcs[1] = q;
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coef[0] = raid6_gfexi[failb-faila];
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coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
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init_async_submit(submit, 0, tx, NULL, NULL, scribble);
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tx = async_sum_product(b, srcs, coef, bytes, submit);
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/* Dy = P+Pxy+Dx */
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srcs[0] = p;
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srcs[1] = b;
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init_async_submit(submit, flags | ASYNC_TX_XOR_ZERO_DST, tx, cb_fn,
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cb_param, scribble);
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tx = async_xor(a, srcs, 0, 2, bytes, submit);
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return tx;
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}
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static struct dma_async_tx_descriptor *
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__2data_recov_5(size_t bytes, int faila, int failb, struct page **blocks,
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struct async_submit_ctl *submit)
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{
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struct dma_async_tx_descriptor *tx = NULL;
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struct page *p, *q, *g, *dp, *dq;
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struct page *srcs[2];
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unsigned char coef[2];
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enum async_tx_flags flags = submit->flags;
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dma_async_tx_callback cb_fn = submit->cb_fn;
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void *cb_param = submit->cb_param;
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void *scribble = submit->scribble;
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int uninitialized_var(good);
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int i;
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for (i = 0; i < 3; i++) {
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if (i == faila || i == failb)
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continue;
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else {
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good = i;
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break;
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}
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}
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BUG_ON(i >= 3);
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p = blocks[5-2];
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q = blocks[5-1];
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g = blocks[good];
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/* Compute syndrome with zero for the missing data pages
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* Use the dead data pages as temporary storage for delta p and
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* delta q
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*/
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dp = blocks[faila];
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dq = blocks[failb];
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init_async_submit(submit, 0, tx, NULL, NULL, scribble);
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tx = async_memcpy(dp, g, 0, 0, bytes, submit);
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init_async_submit(submit, 0, tx, NULL, NULL, scribble);
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tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);
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/* compute P + Pxy */
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srcs[0] = dp;
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srcs[1] = p;
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init_async_submit(submit, ASYNC_TX_XOR_DROP_DST, tx, NULL, NULL,
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scribble);
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tx = async_xor(dp, srcs, 0, 2, bytes, submit);
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/* compute Q + Qxy */
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srcs[0] = dq;
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srcs[1] = q;
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init_async_submit(submit, ASYNC_TX_XOR_DROP_DST, tx, NULL, NULL,
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scribble);
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tx = async_xor(dq, srcs, 0, 2, bytes, submit);
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/* Dx = A*(P+Pxy) + B*(Q+Qxy) */
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srcs[0] = dp;
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srcs[1] = dq;
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coef[0] = raid6_gfexi[failb-faila];
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coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
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init_async_submit(submit, 0, tx, NULL, NULL, scribble);
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tx = async_sum_product(dq, srcs, coef, bytes, submit);
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/* Dy = P+Pxy+Dx */
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srcs[0] = dp;
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srcs[1] = dq;
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init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
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cb_param, scribble);
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tx = async_xor(dp, srcs, 0, 2, bytes, submit);
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return tx;
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}
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static struct dma_async_tx_descriptor *
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__2data_recov_n(int disks, size_t bytes, int faila, int failb,
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struct page **blocks, struct async_submit_ctl *submit)
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{
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struct dma_async_tx_descriptor *tx = NULL;
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struct page *p, *q, *dp, *dq;
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struct page *srcs[2];
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unsigned char coef[2];
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enum async_tx_flags flags = submit->flags;
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dma_async_tx_callback cb_fn = submit->cb_fn;
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void *cb_param = submit->cb_param;
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void *scribble = submit->scribble;
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p = blocks[disks-2];
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q = blocks[disks-1];
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/* Compute syndrome with zero for the missing data pages
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* Use the dead data pages as temporary storage for
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* delta p and delta q
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*/
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dp = blocks[faila];
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blocks[faila] = (void *)raid6_empty_zero_page;
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blocks[disks-2] = dp;
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dq = blocks[failb];
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blocks[failb] = (void *)raid6_empty_zero_page;
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blocks[disks-1] = dq;
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init_async_submit(submit, 0, tx, NULL, NULL, scribble);
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tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
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/* Restore pointer table */
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blocks[faila] = dp;
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blocks[failb] = dq;
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blocks[disks-2] = p;
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blocks[disks-1] = q;
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/* compute P + Pxy */
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srcs[0] = dp;
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srcs[1] = p;
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init_async_submit(submit, ASYNC_TX_XOR_DROP_DST, tx, NULL, NULL,
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scribble);
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tx = async_xor(dp, srcs, 0, 2, bytes, submit);
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/* compute Q + Qxy */
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srcs[0] = dq;
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srcs[1] = q;
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init_async_submit(submit, ASYNC_TX_XOR_DROP_DST, tx, NULL, NULL,
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scribble);
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tx = async_xor(dq, srcs, 0, 2, bytes, submit);
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/* Dx = A*(P+Pxy) + B*(Q+Qxy) */
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srcs[0] = dp;
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srcs[1] = dq;
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coef[0] = raid6_gfexi[failb-faila];
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coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
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init_async_submit(submit, 0, tx, NULL, NULL, scribble);
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tx = async_sum_product(dq, srcs, coef, bytes, submit);
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/* Dy = P+Pxy+Dx */
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srcs[0] = dp;
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srcs[1] = dq;
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init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
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cb_param, scribble);
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tx = async_xor(dp, srcs, 0, 2, bytes, submit);
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return tx;
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}
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/**
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* async_raid6_2data_recov - asynchronously calculate two missing data blocks
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* @disks: number of disks in the RAID-6 array
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* @bytes: block size
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* @faila: first failed drive index
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* @failb: second failed drive index
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* @blocks: array of source pointers where the last two entries are p and q
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* @submit: submission/completion modifiers
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*/
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struct dma_async_tx_descriptor *
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async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
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struct page **blocks, struct async_submit_ctl *submit)
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{
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BUG_ON(faila == failb);
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if (failb < faila)
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swap(faila, failb);
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pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes);
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/* we need to preserve the contents of 'blocks' for the async
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* case, so punt to synchronous if a scribble buffer is not available
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*/
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if (!submit->scribble) {
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void **ptrs = (void **) blocks;
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int i;
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async_tx_quiesce(&submit->depend_tx);
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for (i = 0; i < disks; i++)
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ptrs[i] = page_address(blocks[i]);
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raid6_2data_recov(disks, bytes, faila, failb, ptrs);
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async_tx_sync_epilog(submit);
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return NULL;
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}
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switch (disks) {
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case 4:
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/* dma devices do not uniformly understand a zero source pq
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* operation (in contrast to the synchronous case), so
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* explicitly handle the 4 disk special case
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*/
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return __2data_recov_4(bytes, faila, failb, blocks, submit);
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case 5:
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/* dma devices do not uniformly understand a single
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* source pq operation (in contrast to the synchronous
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* case), so explicitly handle the 5 disk special case
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*/
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return __2data_recov_5(bytes, faila, failb, blocks, submit);
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default:
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return __2data_recov_n(disks, bytes, faila, failb, blocks, submit);
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}
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}
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EXPORT_SYMBOL_GPL(async_raid6_2data_recov);
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/**
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* async_raid6_datap_recov - asynchronously calculate a data and the 'p' block
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* @disks: number of disks in the RAID-6 array
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* @bytes: block size
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* @faila: failed drive index
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* @blocks: array of source pointers where the last two entries are p and q
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* @submit: submission/completion modifiers
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*/
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struct dma_async_tx_descriptor *
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async_raid6_datap_recov(int disks, size_t bytes, int faila,
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struct page **blocks, struct async_submit_ctl *submit)
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{
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struct dma_async_tx_descriptor *tx = NULL;
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struct page *p, *q, *dq;
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u8 coef;
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enum async_tx_flags flags = submit->flags;
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dma_async_tx_callback cb_fn = submit->cb_fn;
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void *cb_param = submit->cb_param;
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void *scribble = submit->scribble;
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struct page *srcs[2];
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pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes);
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/* we need to preserve the contents of 'blocks' for the async
|
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* case, so punt to synchronous if a scribble buffer is not available
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*/
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if (!scribble) {
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void **ptrs = (void **) blocks;
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int i;
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async_tx_quiesce(&submit->depend_tx);
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for (i = 0; i < disks; i++)
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ptrs[i] = page_address(blocks[i]);
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raid6_datap_recov(disks, bytes, faila, ptrs);
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async_tx_sync_epilog(submit);
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||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
p = blocks[disks-2];
|
||||
q = blocks[disks-1];
|
||||
|
||||
/* Compute syndrome with zero for the missing data page
|
||||
* Use the dead data page as temporary storage for delta q
|
||||
*/
|
||||
dq = blocks[faila];
|
||||
blocks[faila] = (void *)raid6_empty_zero_page;
|
||||
blocks[disks-1] = dq;
|
||||
|
||||
/* in the 4 disk case we only need to perform a single source
|
||||
* multiplication
|
||||
*/
|
||||
if (disks == 4) {
|
||||
int good = faila == 0 ? 1 : 0;
|
||||
struct page *g = blocks[good];
|
||||
|
||||
init_async_submit(submit, 0, tx, NULL, NULL, scribble);
|
||||
tx = async_memcpy(p, g, 0, 0, bytes, submit);
|
||||
|
||||
init_async_submit(submit, 0, tx, NULL, NULL, scribble);
|
||||
tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);
|
||||
} else {
|
||||
init_async_submit(submit, 0, tx, NULL, NULL, scribble);
|
||||
tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
|
||||
}
|
||||
|
||||
/* Restore pointer table */
|
||||
blocks[faila] = dq;
|
||||
blocks[disks-1] = q;
|
||||
|
||||
/* calculate g^{-faila} */
|
||||
coef = raid6_gfinv[raid6_gfexp[faila]];
|
||||
|
||||
srcs[0] = dq;
|
||||
srcs[1] = q;
|
||||
init_async_submit(submit, ASYNC_TX_XOR_DROP_DST, tx, NULL, NULL,
|
||||
scribble);
|
||||
tx = async_xor(dq, srcs, 0, 2, bytes, submit);
|
||||
|
||||
init_async_submit(submit, 0, tx, NULL, NULL, scribble);
|
||||
tx = async_mult(dq, dq, coef, bytes, submit);
|
||||
|
||||
srcs[0] = p;
|
||||
srcs[1] = dq;
|
||||
init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
|
||||
cb_param, scribble);
|
||||
tx = async_xor(p, srcs, 0, 2, bytes, submit);
|
||||
|
||||
return tx;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(async_raid6_datap_recov);
|
||||
|
||||
MODULE_AUTHOR("Dan Williams <dan.j.williams@intel.com>");
|
||||
MODULE_DESCRIPTION("asynchronous RAID-6 recovery api");
|
||||
MODULE_LICENSE("GPL");
|
||||
|
|
@ -194,5 +194,13 @@ async_syndrome_val(struct page **blocks, unsigned int offset, int src_cnt,
|
|||
size_t len, enum sum_check_flags *pqres, struct page *spare,
|
||||
struct async_submit_ctl *submit);
|
||||
|
||||
struct dma_async_tx_descriptor *
|
||||
async_raid6_2data_recov(int src_num, size_t bytes, int faila, int failb,
|
||||
struct page **ptrs, struct async_submit_ctl *submit);
|
||||
|
||||
struct dma_async_tx_descriptor *
|
||||
async_raid6_datap_recov(int src_num, size_t bytes, int faila,
|
||||
struct page **ptrs, struct async_submit_ctl *submit);
|
||||
|
||||
void async_tx_quiesce(struct dma_async_tx_descriptor **tx);
|
||||
#endif /* _ASYNC_TX_H_ */
|
||||
|
|
|
|||
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